Just being pedantic

yup. meant 3.2 which is 1/8...

[QUOTE=tommyheadleycox;392060]Greetings, one and all,

I'm posting here because the folks seem genuinely helpful. I need a pinion gear. It's not for a truck but a Maxon coreless motor to go in a big German train I have. I've done a lot of research, but haven't found a match. I'm hoping that someone here might tell me how to proceed. Here's the info about the needed gear:

10 tooth
2 mm bore
7 mm outside diameter (might have once been 7.5- it's now worn.)
5 mm inside diameter (base of teeth)
5 mm length

Update: Please excuse me if this is a duplicate message. I found a source in England that has a 10 tooth, module 0.6, 2 mm bore pinion gear. I also talked with SDP. They did not <think> they had this gear in stock. So I'll try out the gear from England.

I did find some gears that were close. But the fewest number of teeth was 12, not 10. Question: Am I correct in assuming that I can switch from 10T to 12T, as long as I stay with the same module? I understand this will affect top end speed and put more power demand on the motor, but that's not an issue. I just need to achive proper gear mesh.

Last question: Does anyone know if there exists a module between 0.5 and 0.6? I ask because my measurements and scriptasylum tell me the pinion and spur gears are 0.58 module.

Thanks again for all your help.

Tom

Yeah, thats fine- so long as you can adjust the motor side to side to allow for smaller and larger gears then there wont be an issue using 10t or 12t- does just affect the speed and current draw of the motor a little. I think anything between mod .5 & .6 would be very rare or custom/ bespoke for a certain use- an imperial gear might have the equivalent pitch when converted to metric units of measurements.

Thank you very much - this is really useful to know.
Tom

i thought there was metric and imperial .6 though...

See here for metric 0.6... http://www.robinsonracing.com/catalo...tchpinion.html

and losi/duratrax use the other 0.6

http://www3.towerhobbies.com/cgi-bin...?&I=LXUFE5&P=M

We run Mod0.8 and 32p (31.75p) all the time without issues, and that's a pitch difference of 0.25. Using a mod 0.6 for 0.58 is a pitch difference of 0.02.

Have you considered replacing the spur and pinion as a matched set? You might be able to modify the existing spur mount to fit something much more common. Just a thought...

Press fit vs set screw
 

Greetings everyone,

I've found a source for the gears I need. They use set screws or as the English apparently term them, grub screws. But my Maxon motor has no flat on the shaft and is meant to accept press fit pinions as far as I can tell. The shaft is hardened to a Rockwell designated number so creating a flat might be difficult. Have the folks on this forum deal with this problem before?

The source by the way is RW Racing, Mr. Neil Stubbington. Here's the link:
http://www.rwracing.co.uk/about.html

Thanks,
Tom

depending on the amount of torque that will actually be required to get the train moving you may not need to grind a flat spot for the set screw, it will still bite into the round shaft and stop it from spinning. However if you wish to make a flat spot there are a few ways to do it. Start by getting yourself a plastic bag such as a sandwich bag. put the motor in the bag and poke the shaft through, this keeps any metal filings from getting in the motor. If you have some quality files and the shaft isn't to hard you can do it that way. Or you can use a dremel tool with a grinding stone on it to grind a flat spot.

Thanks for the advice. This is helpful. I'm glad to know I can proceed. BTW, the baggie idea is particularly helpful. I was wondering how to protect the motor!

Regards,
Tom